Roasting furnace



June 6, 1933. w J CUMMlNGs ET AL 1,912,973

ROASTING FURNACE Filed Aug. 3, 1931 2 Sheets-Sheet 1 June 6, 1933. w. J. CUMMINGS ET AL 1,912,973

ROASTING FURNACE Filed Aug. 3, 1931 2 Sheets-Sheet 2 YIIIIIIIIIIIIIIIIIIIIIIIIHIIHIIIIIIIIII'IIIIII l/& m

#8116076. Cumming By W JTTOR/VEY Patented Junefi, 1933 UNITED STATES PA OFFICE WILLIAM J. CUMMINGS AND HERBERT e. ouiumnes; or COLUMBIA, CANADA VANCOUVER, BRITISH ROASTIN Gr FURNACE Application filed August 3, 1931, Serial No.

lhis invention relates to improvements in roasting and retorting furnaces and is designed to deal with various classes of mineral ores and shales. I i

A specific object of the invention has been to design a furnace for dealing with cinnabar ores of simple form and character and inexpensive to build.

Another object has been to design a furnace of the continuous type but free of the complications usually found therein.

Still another object has been to design a furnace of the closed type wherein the crushed ores passingthrough are not exposed directly to thefiames, thereby avoiding loss of mineral values in. the gases given off.

A still further object has been to design a furnace that offers a greater measure of protection against salivation of the workman than the usual type of furnace requiring as it does a powerfuland artificial inward draught to control the operation of the furnace and. condensers to avoid this menace.

Our invention differs in its principal essentials from all the well known types of furnaces of this class, such as the Randol, the I'Ieuttner and Scott, the Knox and Osborne, the Livermore and the Cormak-Shirex, wherein vertical shafts with inclined shelving down which the ore is fed and directly exposedto the flames, are used, thereby entailing the use of cooling chambers as condensers with all the attendantcomplication of, dealing with the sticky and usually rich soots as the result of this type of furnace.

Our invention simplifies the construction of furnaces of this character and eifectsagreat economy inthis respect and is equally efficient in operation to the more expensive t e.

ur invention will be more readily understood by reference to the drawings accompanying and forming a part of this application in which:

Figure 1 is a sectional plan of the principal roasting element as installed in a furnace showing the feed hopper conveyor, main con veyor spiral, sweeper spiral, and discharge spiral, also condenser openings and casings with one splral showntherein. This view 554,913 and in Canada September 2, 1930.

also shows condenser manifold header and gearing for driving condenser and discharge spirals. r

' Figure 2 is a cross section of the spiral housing on the line 22 of Figure 1.

Figure 3 is a fragmentary view of the corner of the furnace showing feed hopper and housing of feed conveyor.

Figure 4 is a longitudinal sectionof the main conveyor housing taken on the line 44 r}; of Figure 2 showing intermediate rib between spiral housing, y.

Figure 5 is a diagrammatic longitudinal section of the furnace showing the disposition of the roasting unit therein.

Figure 6.15 a detail cross section on the line 66 of Figure 5.

In these drawings like numerals indicate like parts and 5 represents bearings, 6, 7 and 8 a train of gearing, 9 a drive shaft upon 3? which is secured the small gear 6. Side walls of a brick furnace are representedat 10 and between the walls is an elongated metal casing 11 angularly inclined and suitably mounted within the furnace and having a if? fire-space all around.

The casing 11 is designed to contain and house two metal helices 12 and 13 of different diameter, the larger one being of the nature of a conveyor and is mounted upon the hol- $1, low shaft it carried by the bearings 5. The shaft'lt being hollow is pierced with a number of holes 140; intermediately of the convolution of the helical conveyor forthe purpose of injecting into the ores being roasted 8? any necessary fluxes requisite. The shaft 14 may have its ends fitted with plugs 14a to prevent the escapeof gases from the roasting ores. i a

Between these helices is a metal rib 16 0 rising above the centre line of the spirals but immediately opposite the feed conveyor 20 it forms a complete closure between the helices 12 and 13. The objectsof this rib are firstto prevent the crushed ore in the large 95 helical chamber from entering the compart- V ment occupied by the smallerhelix 13, and second toretain within the small annular he1- 'ical compartment the volatilized metal given is deposited as soot upon the transversely sloping top of the casing 11 and falls beyond the intermediate rib 16 into the compartment occupied by the smaller helix 13 where it is recoverable.

The helices 12 and'13 are driven by the gears 7 and 8 in opposite directions, the larger helix 12 being driven towards the smaller one 13, clockwise, and the small annular helix being driven'in an anti-clockwise direction towards the larger one 12, and the object of this rotation is so that the crushed ore being fed to the main helical conveyor 12 is carried away from the intermediate rib 16 to the opposite side of the casing 11 and thereby removes the risk of the ore entering the compartment occupied by the smaller helix 13, while at the same time the helix 13 revolves towards the condenser openings 24 sweeping the bottom of its compartment clear of any deposited metals and soot and giving movement to the heavy and dense vapours towards the openings 24 where the condenser helices 26 carry them to the 1nani fold header 28.

At and near the driven end of the large helix 12 and on the side of the casing 11 is a flan ed opening 17 and bolted to this open ing is the annular casing 18 with flanged cover plate 19. Mounted within the casing 18 is the helical conveyor 20 driven by the shaft 21 extending through the cover plate 19 and connected to the driving means, not shown. 7

he top of the annular casing 18 is pro vided with an opening 22 to which is connected a feed hopper 23 through which the finely crushed ore is fed. On the opposite side of the casing 11 is a series of flanged openings 24 to which is bolted condenser casings 25 having the helices 26 mounted within them. The helices 26 are all inter-connected by gearing 2'? through themanifold header 28.

The discharge end of the casing 11 opposite the drivenend is open and is flanged around that portion housing the helical conveyor 12. Bolted to this flanged discharge opening is the transverse discharge casing 29 bell-mouthed at one end and having cover plates 30 at the other end to close the same The cover plate 30 is provided with a boss to form a bearing to the shaft 31 which drives the discharge conveyor 32. The shaft 81 is connected in and to the main driving mechanism, as shown in Figure 1.

As the ore is roasted the refuse is delivered by the main spiral conveyor 12 to'the discharge conveyor 32 to be ejected thereby. It is to be noted that at this point the refuse makesa gas-tight joint and prevents the escape of vapour from the roaster. The roasteris built into a suitable furnace designed to burn the class of fuel available and is inclined within the furnace, the highest point being the feed end.

The floor of the fire chamber under the roaster is divided longitudinally by a firebrick partition 83 and in the top of the wall immediately supporting the roaster every other brick is removed and openings 34 provided therein, the object of this being that the main body of fire raverse shall be under themain helical conveyor 12' at the same time a certain amount of the radiant heat permitted under the annular helix 13 suflicient to keep that part at a proper temperature but less than under the main conveyor helix where the actual roasting is done.

The ore to be roasted is first crushed so as to pass through a fort mesh screen and is delivered to the hopper 23 and by it to the feed conveyor 20 and then to the main conveyor helix 12.

It will be noted that the ore being crushed finely makes a -tight joint in the hopper The main conveyor helix 12 causes the ore to traverse the casing 11. It is there subjected to roasting temperatures and gives 05 its sulphur, as the dioxide; and the metal volatilize, the heavy vapour being retained. in the casing 11. This vapour being one hundred times heavier than hydrogen and a density nearly seven times that of air is sluggish and inert. As the roasting proceeds the vapour soon fills the casing 11 and as it rises from the hot ores, it strikes the transverse sloping top of tie casing 11 and is inclined to stick as soot and run towards the smaller helix 13 under the action of the moisture content of the ore.

, As this soot accumulates it becomes heavy in metal and is inclined. to fall but instead of falling in the trough or compartment having the large helical conver -or 12 and thereby being lost by being mixed into the waste refuse ore, it falls beyond he rib 16 and into the smaller compartment housing the annular helix 13.

The function. of the helix 13 is to give movement to the heavy and dense vapour given off by the roasting process and to sweep the walls of its casing clear of the accumulating soots which. carry the volatiliaed metals and deliver same to the openings 24; to which is connected the'condenser casings with their annular helices 26. The 25 are in turn connected to the manifold header 28 to which the annular 'iel'ces 2G deliver ghe heavy vapour from the casing 11 The condenser header 28 is in turn con nected to cooling and complete condensing means that form no partof iis application as the variety and scope of such apparatus is of such extent that any requirements may be filled. V

then I refer to the helices as annr-dai" l'lnean that their appearance or form when viewed endwise is ring-like instead of disklike as is the end view of the conveyor 12. In other words an annular helix is to be understood as one made from a rod in the form of an open coil spring as indicated at 13 and 26 in Figure l.

What we claim is:

1. In an apparatus for roasting ores, the

combination comprising a feed hopper, a

er compartment.

tubular metal casing connected thereto, said casing having a slanting top and a longitudinal upwardly extending rib partially dividing said easing into two compartments of different widths, the larger of said compartments being connected at one end to said feed hopper and having a helical conveyor posi tioned longitudinally therein, a longitudinally disposed annular helix in the smaller of said compartments in virtue of which the volatilized metals given oif in the dense vapours from the larger compartment are recovered through the smaller compartment of said metal casing, said slanting top slanting downwardly from the larger to the smaller compartment.

2. In an apparatus for roasting ores, the combination comprising a feed hopper, a tubular metal casing connected thereto, said casing having slanting top and a longitudinal upwardly extending rib partially di viding said casing into two compartments of different widths the lar er of said com sartmentsbeing connected at one end to said feed hopper and having a helical conveyor positioned longitudinally therein, a longitudinally disposed annular helix in the smaller of said compartments, a series of openings piercing the side of said smaller compartment, other tubular casings having openings at one end which register with the openings in the side of the compartment of smaller width, a manifold header connected to said other casings, annular helices longitudinally positioned within said other casings, said helices adapted to draw products from said compartments and into said manifold header,

in virtue of which the volatilized metals given off in the dense vapours from the larger compartment are recovered through the smaller compartment, said slanting top slanting downwardly from the larger to the small- 3. In an apparatus for roasting ores, the combination comprising a feed hopper, a tubular metal casing connected thereto, said casing having a slanting top and a longitudinal upwardly extending rib partially rib dividing said easing into two compartments of different widths,the larger of said compartments being connected at one end to said feed hopper and having a helical conveyor positioned longitudinally therein, a longitudinally disposed annular helix in the smaller of said compartments, the side of said smaller compartment having a series of openings, other tubular casings having openings at one tioned within said other casings, said helices adapted to draw productsfrom said compartments and into said manifold header, the

slanting top of said casing serving to cause the accumulating soots from the dense vapours of the larger compartment to stick and run towards the smaller compartment under the action of the moisture content of the ore whereby the said soots are swept by the first mentioned annular helix from the slanting top and deposited with the volatilized metals into said smaller compartment, thereby constituting means for recovering the volatilized metals given oil in the dense vapours from the larger compartment in the smaller compartment said slanting top slanting downwardly from the larger to the smaller compartment.

4. In an apparatus for roasting ores, the combination comprising a feed hopper, a tubular metal casing connected thereto, said casing having a slanting top and a longitudinal upwardly extending rib partially dividing said easing into two compartments of different widths, the larger of said compartments being connected at one end tosaid feed hopper and having a helical conveyor positioned longitudinally therein, a longitudinally disposed annular helix in the smaller of said compartments, the side of said smaller compartment having a series of openings,

other tubular casings having openings at one end which register with the openings in the side of the compartment of smaller width, a manifold header connected to said other casings, annular helices longitudinally positioned within said other casings, said helices adapted to draw products from said compartments and into said manifold header, the slanting top of said casing serving to cause the accumulating soots from the dense vapours of the larger compartment to stick and run towards the smaller compartment under the action of the moisture content of the ore whereby the said soots are swept by the first mentioned annular helix from the slanting top and deposited with the volatilized metals into said smaller compartment, thereby c011- stituting means for recovering the volatilized metals given off in the dense vapours from the larger compartment in the smaller compartment, the annular helices which are positioned in saidother casing serving as a means to deliver said vapours and volatilized metals into said manifold header.

In testimony whereof we aflix our signatures. I

WILLIAM J. CUMMINGS. HERBERT Gr. CUMMINGS. 

